The analysis of the dosage of H-2 antigens in material aneuploid for chromosome 17. These analyses will be carried out in whole embryos and in cells cultured from embryos either wholly or partially trisomic for chromosome 17. Embryos monosomic for chromosome 19 will be compared with normal embryos with regard to overall rates of protein synthesis and the synthesis of individual polypeptide chains. The development of monosomies 1 and 12, which reach implantation, will be analyzed further to determine the time which the lethal effects are expressed. The comparative studies of protein synthesis in aneuploid and normal embryos will be carried out using human cell strains trisomic for chromosome other than 21. In addition, more studies will be done using mouse embryos aneuploid for chromosomes 1 and 16.